The difference and application of LAN, WAN, WAN and LAN multiplexing, RJ45, RS232, RS485, DB9, AI, DI, AO, DO, USB?

1. WAN port is an interface to connect external network: the common PPP dialing can be reused for LAN port (RJ45 network access)

2. LAN port is an interface to connect internal network: it can be connected to network port lower machine (RJ45 network output)

3. WAN and LAN multiplexing: indicates that the port can be used as LAN port or WAN port. Industrial cellular router will distinguish itself whether user insert external network or internal network

4. RJ45 interface: refers to RJ45 network can plug up, it is likely to be LAN, or may be WAN. Also known as crystal head, the connector is composed of a plug (a connector, a crystal head) and a socket (module). The plug has 8 grooves and 8 contacts. RJ is the abbreviation of Registered Jack, meaning "registered socket". It is widely used in the connection between LAN and ADSL broadband devices

5. RS232 port: transmission rate is low, in asynchronous transmission, the baud rate is 20Kbps. It only supports point to point communication; from the connection, RS232 is three wire system, it can only transmit 15 meters, full duplex transmission

6. DB9 interface: RS232 standard specifies the use of a DB25 connector with 25 feet. The signal contents of each pin of the connector are specified, and the levels of all kinds of signals are specified. DB25 pin serial generally use only 2 (RXD), 3 (TXD), 7 (GND), with the continuous improvement of equipment, now DB25 needle is seldom seen, it was replaced by DB9 interface, DB9 pin use 2 (RXD), 3 (TXD), 5 (GND) , so RS232 interface is now called DB9

7. RS485 port: the maximum data transmission rate is 10Mbps. RS485 is two line system; the farthest can transmit 3,000 meters; half duplex transmission; support bus form communication. The RS485 interface allows up to 128 transceivers on the bus. It has multi station capabilities, so that users can make use of a single RS-485 interface to facilitate the establishment of a network of devices

8. AI: DC analog input, usually 0-5V or 4-20MA standard signal input

9. DI: switch quantity input, reflecting the state of the switch is divided or fit

10. AO: DC analog output, usually 0-10V or 4-20MA signal output, as a signal adjustment

11. DO: switch output, can be relay and so on.

12. USB port: plug and play, instead of serial port and parallel port, become the mainstream of intelligent equipment interface. Baima BMR500 industrial cellular router is marked with a USB interface, which can connect U disk, mobile hard disk and other storage devices, so as to facilitate local storage of router job logs. Industrial cellular router can also upgrade the program locally by connecting U disk, mobile hard disk, and so on.